The present invention relates to a composition of a self-encapsulating polymer-containing solution and a process for the in-flight encapsulation of particles such as insecticides, fungicides, herbicides, etc., contained therein. More specifically, the present invention relates to the in-flight encapsulation of said particles during passage between the egress of a spray apparatus and a target.
Heretofore, the encapsulation of a chemical substance within an enveloping polymeric membrane has been well recognized by the art. For example, U.S. Pat. Nos. 3,242,051, 3,265,629, 3,575,882, and 3,607,776 all relate to processes dependent upon phase separation and polycondensation reactions. Specifically, the 3,242,051 patent relates to preparing a solution of a liquid phase-forming micromolecular polymer in a first non-aqueous liquid, dispersing in said solution a plurality of individual discreet particles, adding a second liquid soluble in the first liquid, but not soluble with regard to said micromolecular polymer, whereby phase separation is induced and precoats the dispersed particles, settling the polymer-rich precoat, separating the precoated particles, suspending the precoated particles in an aqueous solution of a gel, and using phase separation so as to cause the formation of a colloidal-enriched phase and the encapsulation of each of these suspended precoated particles, and cooling.
U.S. Pat. No. 3,265,629 is similar but relates to the application of two coatings to the particles, namely a solid lipid and a polymer.
U.S. Pat. No. 2,648,609 relates to an air suspension technique wherein a sugar solution is sprayed onto a suspended item such as candy, gum, etc. Another technique heretofore utilized is the utilization of charging a first solution with ions so that the solution exhibits a specific charge, applying an opposite charge to a second solution, and then coating the first solution with the second solution via air flow.
U.S. Pat. No. 3,202,533 relates to the encapsulation of liquids by the use of a fluidized bed wherein the fluidized liquid is frozen and spray coated.
Common to all such above-described inventions and prior art processes is the utilization of multiple compounds or compositions of matter as well as the necessity of processing the encapsulated or microencapsulated article prior to usage or application. Moreover, costly and complex processing equipment as well as difficult technology is required to produce articles of a defined size and to meet mandatory environmental controls or regulations.
In contrast, the present invention relates to but a single self-encapsulating polymer-containing solution or dispersion. Moreover, the invention pertains to encapsulation of a particle phase, either liquid or solid or combined, via a polymer through in-flight encapsulation; that is, during the passage from the spraying or ejection equipment to the target substance or area, including an agricultural or forested area.
Compounds such as "PRO-TEC," manufactured by Agro-K Corporation, concentrate on the formation of a semi-permeable membrane which may spread over leaf surfaces because of its good surfactant properties. Difficulties in application of these membrane chemicals formed from hydrophilic polymers are avoided by a self-encapsulating, non-hydrophilic polymer-containing solution or dispersion of the present invention. Moreover, "PRO-TEC" is a film and does not relate to encapsulated particles.
U.S. Pat. No. 2,972,545 to Briskin; No. 3,015,128 to Somerville; No. 3,681,089 to Gould; No. 3,681,248 to Gould; No. 3,932,602 to Sweger; and No. 3,939,099 to Tusa relate to membrane formation, and the like, and are not pertinent concerning in-flight encapsulation of particles.